Stem Lab Review - Lab Exam 1

Slide 1:
External Woody Stem Morphology		 Identify all tissues shown and give the function of each.  Note that the terminal bud contains the apical meristem thus produces growth in length.  Nodes are regions of lateral growth and produce leaves and lateral stems.   Axillary buds are located on the nodes and can develop into leaves or lateral stems.  Axillary buds are found in the axil, angle, between the stem and the leaf petiole.  An internode is the space between two nodes.  Lenticels are small openings in the peridrem that allow gas excahnge.  A terminal bud scale scar is the lacation of the termainal bud during a previous winter.
Slide 2:
Monocot Stem Cross Section. 
100X		 This slide has both a low magnification photo of the stem and a high magnification of the vascular bundle.  Be able to identify all tissues identified and give their functions.  Bundles of xylem and phloem tissue are called vascualr bundles.  Each vascular bundle is surrounded by a layer of collenchyma or sclerenchyma tissue called the bundle sheath.  Xylem tissue transports water upward and phloem transports food in all directions.  The epidermis is the outer protective layer on the outside of the stem.  Collenchyma cells are usually found inside the epidermis and contribute to support in the stem.  Parenchyma cells are involved in food and water storage.
Slide 3:
Monocot Stem Cross Section.  Smilax stem c.s. showing well developed xylem and phloem tissues.  400X		 Note the regions of xylem and phloem tissue.   There is no air space in the Smilax vascular bundle as in Zea.   Note companion cells and sieve tube members that make up phloem tissue.
Slide 4:
Monocot Stem Cross Section.  Zea stem c.s. showing well developed xylem and phloem tissues.  400X		 Note the regions of xylem and phloem tissue.   There is an air space in the xylem region of the Zea vascular bundle.   Note companion cells and sieve tube members that make up phloem tissue.
Slide 5:
Woody Dicot Stem Cross Section. 
100X 		This is a low magnification view.   Be able to identify all tissues identified and give their functions.  Note that the pith is a region of parenchyma tissue located in the center of the stem.  Just outside the pith is the primary xylem, xylem originally produced by the apical meristem.  Three bands of secondary xylem is located outside the primary xylem.  Large cells in the secondary xylem are spring wood and smaller ones are summer wood when growth is slower.   The annual ring is the point where spring wood and summer wood are in contact.   Outside the vascualr cambium is the bark which contains phloem and to the outside the periderm.
Slide 6:
Woody Dicot Stem Cross Section. 
100X		 A second view.  Note all the same structures seen in slide 5.
Slide 7:
Woody Dicot Stem Cross Section		 This slide has a low, medium and high magnification photo.  Again be able to identify all tissues identified and give their functions.   In the 200X photo note the cortex, a region of parenchyma tissue between the regions of phloem.  In the phloem identify phloem fibers (sclerenchyma fibers) and functional phloem.  Note the lacation of the cork cambium and cork layers to the outside in the high magnification view.
Slide 8:
Woody Dicot Stem Cross Section		 This photo is a view of the phloem region of the stem at a magnification of approximately 200X.
Slide 9:
Woody Dicot Stem Cross Section 400X		 High magnification view of the phloem region of the stem.  Note phloem fibers (redish sclerenchyma fibers) and functional phloem (thin bluish to greenish walls).  Also idnetify the vascualr cambium and periderm.   Know the function of each.
Slide 10:
Herbaceous Dicot Stem Cross Section
200X		 Magnification ofn this slide is approximately 200X.    Identify all tissues shown and give the function of each.
Slide 11:
Herbaceous Dicot Stem Cross Section
400X		 This is a high magnification photo of the vascular bundle.  Note the location of the vascular bundle between the xylem and phloem tissue.  Also note the difference in appearance of the phloem and the phloem fiber cap to the outside.
Slide 12:
Herbaceous Dicot Stem Cross Section
400X		 Another high magnification photo of the vascular bundle.  Note the location of the vascular bundle between the xylem and phloem tissue.  Also note the difference in appearance of the phloem and the phloem fiber cap to the outside.
Slide 13:
Herbaceous Dicot Stem Cross Section
400X
 Still another high magnification photo of the vascular bundle.  Note the location of the vascular bundle between the xylem and phloem tissue.  Also note the difference in appearance of the phloem and the phloem fiber cap to the outside.
Slide 14:
Longitudinal Section of a Terminal Bud		 Identify all tissues shown and give the function of each.  Remember that tissues produced by the apical meristem are primary tissues and produce growth in length as compared to the vascular cambium which produces secondary tissues and results in growth in diameter.  The leaf primordium will develop into a leaf, while a bud primordium will develop into an axillary bud.  The procambium will develop into the vascular cambium and produce xylem and phloem of the vascular bundles.   The ground meristem becomes the parenchymous cortex and pith and the protoderm develops into the epidermis.  A trichome is a dermal hair.